Armature for dynamo-electric machines



(No Model.)

J. T. MORROW. I v ARMATURE FOR DYNAMO ELECTRIC MAGHINES.

Pat'entedSept.5,1893.

I WITNEESES UNITED STATES PATENT OFFICE.

JOHN T. MORROW, OF LYNN, ASSIGNOR TO THE GENERAL ELECTRIC COMPANY,BOSTON, MASSACHUSETTS.

ARMATURE FOR DYNAMO-ELECTRIC MACHINES.

SPECIFICATION forming part of Letters Patent No. 504,401, datedSeptember 5, 1893.

Application filed May 13, 1893. Serial No. 474080. (No model.)

To all whom it may concern.-

Be it known that 1, JOHN T. MORROW, acitizen of the United States,residing at Lynn, in the county of Essex and State of Massachusetts,have invented certain new and useful Improvements in the Construction ofArmatures, of which the following is a specification.

My invention relates to the construction of armatures its object beingto provide efficient and economical meansfor building up a laminatedcore and securing it to its support or carrier.

In carrying out my invention I provide an internal cylindricalsupporting shell, preferably carried by the usual armature spiders keyedto a shaft, and on the outer surface of said supporting shelllongitudinal grooves are cut, into which corresponding projections onthe inner surface of an annular armature core are adapted to fit,preferably making a dovetail or undercut joint. The core itself iscomposed of segmental laminae of such proportions that a predeterminednumber of them make one layer of the core; and in adjacent layers thesegments are so arranged as to break joints. The said segments areprovided at their inner edges with projections adapted to fit thegrooves on the supporting shell, and registering with each other whenthe core is assembled.

In the accompanying drawings, Figure l is an end elevation of anarmature constructed in accordance with my invention, and Figs. 2, 3 and4 are modifications in the shape of the grooves and projections wherebythe parts are united.

Referring to Fig. 1, the cylindrical supporting shell A is carried onspiders A keyed to a shaft A in the ordinary manner. At regularintervals along the outer surface of said supporting shell A arelongitudinal undercut grooves a, into which fit the dovetail projectionsb, on the laminae B. In making up an armature, the spiders andsupporting shell are first assembled, and the laminae of sheet ironpunched out in the shape indicated in Fig. 1 are slipped over thesurface of the said shell with the projections a in the grooves b. Afterone layer is in place, another, breaking joints with the first, is puton, and so on, until the armature is completed.

The dotted lines in Fig. 1 indicate the edges of the laminae insuccessive layers, showing the manner of breaking joints.

It is obviously unnecessary to have the dovetail projections exactly fitthe grooves, as shown in Fig. 1, and this is moreover manifestlyundesirable, since much more care is thereby rendered necessary both inpunching the laminae and in finishing the grooves. Slight modificationsare therefore shown in Figs. 2, 3 and 4.. In Fig. 2 the outer corners ofprojection b are rounded as shown at I), while the outer edges of thegroove a are rounded as shown at a. A firm connection is thus affordedbetween the parts by the fit of the beveled edges of the groove andprojection, while the necessity of a perfect fit at the acute angles,which would be difficult of attainment, is obviated. In Fig. 3 insteadof rounding the edges of the grooves a, the laminae are punched so as tohave a recess b at the inner acute angles of the dovetail projections.In all of these arrangements, however, the projection 1) extends to thebottom of the groove (1, necessitatinga careful milling thereof as wellas a smooth edge on said projection, in order to render the partsreadily assembled. It is therefore preferable to chamber the groove asshown at b in Fig. 4..

The die used in punching out the laminae is now simple in form as inFig. 1, while imperfections caused by dulling thereof at the acuteangles where such imperfections are most likely to manifest themselves,make no material differencein the strength of construction.

I am aware of Patent No. 493,337 granted to I-Iorace F. Par-shall March14, 1893, and therefore do not claim broadly an annular core sup portedby and dovetailed to an internal cylindrical support, but confine myselfto a core made up of segmental laminee punched with internal dovetailprojections. It is obviously of material advantage to make the laminaesegmental rather than annular since the material from which they arepunched can in this way be out much less to waste While by so assemblingconsecutive layers as to break joints, as above set forth, a practicallysolid structure is obtained.

Afurther improvement consists in the modifications in the shape of thedovetail connec tions, as described, which render the parts much morereadily assembled. By making the core with internal dovetail projectionsintegral therewith a greater depth of free iron 5 for the traverse ofmagnetism is obtained.

What I claim as new, and desire to secure by Letters Patent, is

1. An armature for dynamo electric machines, comprising a cylindricalsupporting Io shell having longitudinal undercut grooves in its outersurface, and an annular core made up of segmental laminae fittingthereon and provided with internal dovetail projections integraltherewith and engaged by said unr5 dercut grooves, as described.

2. An armature core comprising layers of segmental laminae dovetailed toan internal JOHN T. MORROW.

Witnesses:

JOHN W. GIBBONEY, BENJAMIN B. HULL.

